Antibacterial studies of Ag@HPEI@GO nanocomposites and their effects on fouling and dye rejection in PES UF membranes

A series of polyethersulfone membranes containing [email protected]@GO composite was fabricated using non-solvent induced phase separations (NIPS) to mitigate against biofilm causing bacteria and modulate solute rejection. All materials produced and used were fully characterised using a combination of appropriate physicochemical techniques including FTIR, XRD, BET, SEM, AFM. The GO-based fillers exhibited bactericidal activities. The bactericidal activities of GO, [email protected] against Escherichia Coli (E. coli) were observed at 8 mg mL−1 whilst [email protected]@GO composites exhibit bactericidal activities against E. coli at 4 mg mL−1. Against Klebsiella pneumonia (K. pneumonia), GO bactericidal activities were observed at 8 mg mL−1, whilst [email protected] and [email protected]@GO bactericidal activities on K. pneumonia were observed at 4 mg mL−1. Against Staphylococcus aureus (S. aureus), GO exhibit bactericidal activities at 8 mg mL−1, [email protected] and [email protected]@GO composites exhibit bactericidal activities on S. aureus at 4 mg mL−1. The aforementioned microorganisms are among the microorganism that causes biofilm formation on surfaces. The membrane performance was assessed by measuring pure water flux, solute rejections and fouling propensity with three different organic dye molecules and bovine serum albumin (BSA). All composite membranes (GO/PES, [email protected]/PES, and [email protected]@GO/PES) exhibited increased hydrophilicity and higher pure water flux compared to the baseline PES membranes with concomitant increase in fouling resistance, The observed flux recovery ratios (FRR) were 80% (GO/PES), 70% ([email protected]/PES) and 69% ([email protected]@GO/PES) respectively compared to the 45% FRR observed for the baseline PES membrane after BSA fouling. Congo red (CR) used as an indicator for molecular cut-off of UF membranes was rejected above 95% by all nanocomposite membranes. Furthermore, the nanocomposite membranes-maintained rejection for the positively charged methylene blue (MB) of above 90% whilst rejection observed for amaranth (AR) dye decreased from 80 to 58% with increasing filler content in the PES matrix. The results demonstrate the positive influence of GO, [email protected] and Ag/[email protected] nanofillers on flux, fouling and solute rejection performance of resultant PES nanocomposite membranes.